Answer:
equation: 24.50 = 2.50x + 3.25(8 -x)
solution: x = 2
Step-by-step explanation:
You can solve this problem by writing an equation for the total value of the purchase. It is the sum of products of the number of notebooks and their cost.
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If x of the 8 notebooks were the least expensive, then (8-x) were the most expensive.
total cost = cost of least expensive + cost of most expensive
24.50 = 2.50x + 3.25(8 -x) . . . . . . . . one way to write the equation
24.50 = -0.75x +26.00 . . . . . . . . . simplified equation
-1.50 = -0.75x . . . . . . . . . . . . . . . after subtracting 26
2 = x . . . . . . . . . . . . divide by -0.75
Two (2) of the least-expensive notebooks were purchased.
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<em>Additional comments</em>
This problem statement asks "which equation," but does not provide any choices. We hope that one of the equations shown above will give you a sufficient clue to make the correct answer choice.
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We like to let the variable represent the <em>most</em>-expensive contributor in the problem. That way, it ends up with a <em>positive</em> coefficient when the equation is simplified. There tends to be fewer errors when the math is done with positive numbers.
